feat(compiler-cli): expose ngtsc as a TscPlugin (#27806)

This lets us run ngtsc under the tsc_wrapped custom compiler (Used in Bazel)
It also allows others to simply wire ngtsc into an existing typescript compilation binary

PR Close #27806

package.json

@@ -36,7 +36,7 @@
     "@angular-devkit/core": "^7.0.4",
     "@angular-devkit/schematics": "^7.3.0-rc.0",
     "@bazel/karma": "~0.22.1",
-    "@bazel/typescript": "~0.22.1",
+    "@bazel/typescript": "0.22.1-7-g68fed6a",
     "@schematics/angular": "^7.0.4",
     "@types/angular": "^1.6.47",
     "@types/chokidar": "1.7.3",

packages/compiler-cli/index.ts

@@ -24,3 +24,4 @@ export {CompilerOptions as AngularCompilerOptions} from './src/transformers/api'
 export {NgTools_InternalApi_NG_2 as __NGTOOLS_PRIVATE_API_2} from './src/ngtools_api';
 
 export {ngToTsDiagnostic} from './src/transformers/util';
+export {NgTscPlugin} from './src/ngtsc/tsc_plugin';

packages/compiler-cli/src/ngtsc/synthetic_files_compiler_host.ts

@@ -0,0 +1,96 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {PluginCompilerHost} from '@bazel/typescript/tsc_wrapped/plugin_api';
+import * as ts from 'typescript';
+
+/**
+ * Extension of the TypeScript compiler host that supports files added to the Program which
+ * were never on disk.
+ *
+ * This is used for backwards-compatibility with the ViewEngine compiler, which used ngsummary
+ * and ngfactory files as inputs to the program. We call these inputs "synthetic".
+ *
+ * They need to be program inputs because user code may import from these generated files.
+ *
+ * TODO(alxhub): remove this after all ng_module users have migrated to Ivy
+ */
+export class SyntheticFilesCompilerHost implements PluginCompilerHost {
+  /**
+   * SourceFiles which are added to the program but which never existed on disk.
+   */
+  syntheticFiles = new Map<string, ts.SourceFile>();
+
+  constructor(
+      private rootFiles: string[], private delegate: ts.CompilerHost,
+      generatedFiles: (rootFiles: string[]) => {
+        [fileName: string]: (host: ts.CompilerHost) => ts.SourceFile | undefined
+      }, ) {
+    // Allow ngtsc to contribute in-memory synthetic files, which will be loaded
+    // as if they existed on disk as action inputs.
+    const angularGeneratedFiles = generatedFiles !(rootFiles);
+    for (const f of Object.keys(angularGeneratedFiles)) {
+      const generator = angularGeneratedFiles[f];
+      const generated = generator(delegate);
+      if (generated) {
+        this.syntheticFiles.set(generated.fileName, generated);
+      }
+    }
+  }
+
+  fileExists(filePath: string): boolean {
+    if (this.syntheticFiles.has(filePath)) {
+      return true;
+    }
+    return this.delegate.fileExists(filePath);
+  }
+
+  /** Loads a source file from in-memory map, or delegates. */
+  getSourceFile(
+      fileName: string, languageVersion: ts.ScriptTarget,
+      onError?: (message: string) => void): ts.SourceFile|undefined {
+    const syntheticFile = this.syntheticFiles.get(fileName);
+    if (syntheticFile) {
+      return syntheticFile !;
+    }
+    return this.delegate.getSourceFile(fileName, languageVersion, onError);
+  }
+
+  get inputFiles() { return [...this.rootFiles, ...Array.from(this.syntheticFiles.keys())]; }
+
+  fileNameToModuleId(fileName: string) {
+    return fileName;  // TODO: Ivy logic. don't forget that the delegate has the google3 logic
+  }
+
+  // Delegate everything else to the original compiler host.
+
+  getDefaultLibFileName(options: ts.CompilerOptions): string {
+    return this.delegate.getDefaultLibFileName(options);
+  }
+
+  writeFile(
+      fileName: string, content: string, writeByteOrderMark: boolean,
+      onError: ((message: string) => void)|undefined,
+      sourceFiles: ReadonlyArray<ts.SourceFile>|undefined): void {
+    this.delegate.writeFile(fileName, content, writeByteOrderMark, onError, sourceFiles);
+  }
+
+  getCanonicalFileName(path: string) { return this.delegate.getCanonicalFileName(path); }
+
+  getCurrentDirectory(): string { return this.delegate.getCurrentDirectory(); }
+
+  useCaseSensitiveFileNames(): boolean { return this.delegate.useCaseSensitiveFileNames(); }
+
+  getNewLine(): string { return this.delegate.getNewLine(); }
+
+  getDirectories(path: string) { return this.delegate.getDirectories(path); }
+
+  readFile(fileName: string): string|undefined { return this.delegate.readFile(fileName); }
+
+  trace(s: string): void { console.error(s); }
+}

packages/compiler-cli/src/ngtsc/tsc_plugin.ts

@@ -0,0 +1,69 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {PluginCompilerHost, TscPlugin, createProxy} from '@bazel/typescript/tsc_wrapped/plugin_api';
+import * as ts from 'typescript';
+
+import {SyntheticFilesCompilerHost} from './synthetic_files_compiler_host';
+
+export class NgTscPlugin implements TscPlugin {
+  constructor(private angularCompilerOptions: unknown) {}
+
+  wrap(program: ts.Program, config: {}, host: ts.CompilerHost) {
+    const proxy = createProxy(program);
+    proxy.getSemanticDiagnostics = (sourceFile: ts.SourceFile) => {
+      const result: ts.Diagnostic[] = [...program.getSemanticDiagnostics(sourceFile)];
+
+      // For demo purposes, trigger a diagnostic when the sourcefile has a magic string
+      if (sourceFile.text.indexOf('diag') >= 0) {
+        const fake: ts.Diagnostic = {
+          file: sourceFile,
+          start: 0,
+          length: 3,
+          messageText: 'Example Angular Compiler Diagnostic',
+          category: ts.DiagnosticCategory.Error,
+          code: 12345,
+          // source is the name of the plugin.
+          source: 'Angular',
+        };
+        result.push(fake);
+      }
+      return result;
+    };
+    return proxy;
+  }
+
+  createTransformers(host: PluginCompilerHost) {
+    const afterDeclarations: Array<ts.TransformerFactory<ts.SourceFile|ts.Bundle>> =
+        [(context: ts.TransformationContext) => (sf: ts.SourceFile | ts.Bundle) => {
+          const visitor = (node: ts.Node): ts.Node => {
+            if (node.kind === ts.SyntaxKind.ClassDeclaration) {
+              const clz = node as ts.ClassDeclaration;
+              // For demo purposes, transform the class name in the .d.ts output
+              return ts.updateClassDeclaration(
+                  clz, clz.decorators, node.modifiers, ts.createIdentifier('NEWNAME'),
+                  clz.typeParameters, clz.heritageClauses, clz.members);
+            }
+            return ts.visitEachChild(node, visitor, context);
+          };
+          return visitor(sf) as ts.SourceFile;
+        }];
+    return {afterDeclarations};
+  }
+
+  wrapHost(inputFiles: string[], compilerHost: ts.CompilerHost) {
+    return new SyntheticFilesCompilerHost(inputFiles, compilerHost, this.generatedFiles);
+  }
+
+  generatedFiles(rootFiles: string[]) {
+    return {
+      'file-1.ts': (host: ts.CompilerHost) =>
+                       ts.createSourceFile('file-1.ts', 'contents', ts.ScriptTarget.ES5),
+    };
+  }
+}

yarn.lock

@@ -160,10 +160,10 @@
     semver "5.6.0"
     tmp "0.0.33"
 
-"@bazel/typescript@~0.22.1":
-  version "0.22.1"
-  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-0.22.1.tgz#b52c00e8560019e2f9d273d45c04785e0ec9d9bd"
-  integrity sha512-88DaCCnNg8rPlKP0eAQEZuoiJkEPeiItpUS3oBR1sFQNBRJb56D25ahK8+N6LJk4qaH+ZQ1/AHOPDhfEEWvDzA==
+"@bazel/typescript@0.22.1-7-g68fed6a":
+  version "0.22.1-7-g68fed6a"
+  resolved "https://registry.yarnpkg.com/@bazel/typescript/-/typescript-0.22.1-7-g68fed6a.tgz#d6340fbfcfdeb3893e66ec8a435b850cfa83d60f"
+  integrity sha512-EBPxbge/RBas7zSLvCjUgtpIVdjU+AgZ6YyCMTaYcn4hzD1eYQUpGHT+fa9/icHvk/84wWGXCFRb1+uZsBofVA==
   dependencies:
     protobufjs "5.0.3"
     semver "5.6.0"